Gas turbine control system with ambient temperature compensation



April 21, 1953 s. w. JAMES 2,636,130 GAS TURBINE CONTROL SYSTEM WITH AMBIENT TEMPERATURE COMPENSATION Filed Aug. 2. 1951 Patented Apr. 21, 1953 GAS TURBINE CONTROL SYSTEM WITH AMBIENT TEMPERATURE COMPENSA- TION Stanley W. James, Detroit, Mich., assignor to Allis-Chalmers Manufacturing Company, Milwaukee, Wis.

Application August 2, 1951, Serial No. 240,013

11 Claims.

This invention relates in general to control systems and in particular to control systems for the combustion chambers of gas turbines.

Somegas turbines are operated in two distinct phases, during the first of which the turbine speed is maintained constantat a predetermined minimum value and the fuel supplied to the combustion chamber is increased to increase the turbine temperature and power. When the turbine temperature reaches a predetermined maximum value, the turbine enters the second phase of its operation, during which the turbine temperature is maintained substantially constant at the maximum value and the turbine speed is increased by the throttle acting on the governor to increase turbine power. During the first phase, the governor speed setting remains constant at thepredetermined minimum value, and the turbine throttle is moved to increase the fuel supplied to the turbine combustion chamber. The position of the throttle at which the maximum turbine temperature is reached varies with the ambient temperature, this maximum temperature being reached at a higher throttle position when the ambient temperature is low than when the ambient temperature is high. To insure that the turbine is always at the predetermined maximum value when the governor speed setting is changed from the minimum setting by the throttle, it is desirable to compensate for variations in the ambient temperature. This is especially necessary where the turbine is utilized to drive an apparatus, such-as a locomotive, which is subjected to extreme variations in ambient temperature in dependence upon the location and season of operation of the apparatus.

It is therefore an object of this invention to provide an improved control system for a combustion chamber supplying motive gas to a gas turbine.

It is an additional object of this invention to provide a control system for a combustion chamber supplying motive gas to a gas turbine in which system the effect on the turbine of variations in the ambient temperature is compensated for in an adjustable governor means.

Objects and advantages other than thos set forth above will be apparent from the following description when read in connection with the accompanying drawing, the single figure of which diagrammatically illustrates the circuits and apparatus of one embodiment of this invention.

Referring to the drawing by character of ref erence, numeral denotes a gas turbine supplied with motive gas from a combustion chamber 7.

Chamber I is supplied with compressed combustion air through a pipe 8 from a compressor! driven'by turbine 6 through a shaft I l. Turbine 6 may be utilized to drive any suitable load, such as direct current generator l2 connected to shaft H either directly or through suitable reduction gearing. Generator !2 has an armature 'IZa-and a field winding [2b. Armature I2a supplies'cub rent to any suitable electrical load, and if the turbine is utilized to drive a, locomotive, such load may comprise the armature l3a of a traction motor 13 having a series field winding l3b. Armature [2a is connected to armature l3a'and field winding [32) through the contacts IOco'f a solenoid relay [0 having a contact bridging member Nb and an operating coil lOa. It Will be understood that although only one main generator and one traction motor have been illustrated, additional machines may be provided if required to produce additional traction power.

Field winding [2b of generator 12 is supplied with current from any suitable controllable direct current source, such as the armature Ha of an amplifying excit'er I! having a self-exciting field winding [lb and a control field winding llc. Field winding llb is connected across armature Ila in series with an adjustable resistor [8, while field winding lie is connected in series with a battery 19 and adjustable resistance means in the form of adjustable resistors 2|, 22.

Combustion chamber 1 is provided with a fuel burner 23 to which fuel is supplied from a fuel regulating valve 24. Valve 24 is of a conventional type in which the flow of the fuel through the valve from a pipe 25 connected to a fuel source is controlled by a variable control pressure impressed on a valve actuator 20 from a pipe 26. The greater the pressure in pipe 26, the greater is the opening of valve 24 to increase the flow of fuel to burner 23. Pipe 25 is connected to the output chamber 33a of fluid pressure controlled valve 3|, herein referred to as a fuel totalizer. The totalizer is provided with flexible diaphragms, such as diaphragms 311', 3l7' which, together with adjacent rigid partitions, such as partitions 31k, 311 form input chambers 3Ib, 3lc, 31d, 31c, 3i Sly and SM which are adapted to receive fluid input control pressures for controlling the output pressure in chamber 3 I a.

The diaphragms are connected together to a movable rod 3 I m which is moved in response to variations in the algebraic sum of the input and output pressures acting on the totalizer. During part of its stroke, rod Sim cooperates with a,

valve stem Sin, which is then fixed, to variably open an exhaust port 3 !1'. During the remainder of its stroke, rod Mm actuates valve stem 3m to control a supply port Sip. When stem am is moved to the right by rod 3lm, the stem closes exhaust port Mr and opens supply port 31p admitting air to chamber 3la from a pipe 32 connected to a suitable source of air under pressure, such as a reservoir 33. When connecting rod Sim is moved sufilciently to the left, valve stem 3m closes supply port Sip and opens exhaust port 3 ii to allow air from chamber 3m to escape to atmosphere through a chamber provided in rod Sim and in partition am. In an intermediate position, rod Sim maintains both ports 31p, 3lr closed. Thus, totalizer 3| acts to add or subtract the pressures in the totalizer input and output chambers to control the output pressure, with movement of rod 3lm to the right causing air to be admitted to chamber 3 la until the pressure therein increases to a value balancing the algebraic sum of the pressures on the diaphragms, and movement of rod 3Im to the left causing a reduction in pressure in chamber Sia until the pressures are again balanced on the diaphragms. A loading spring 3!?) may be utilized to put an initial bias or loading pressure in chamber 3 la.

Input chamber file of totalizer 3| receives a control input pressure through a pipe 2? from the output chamber 28a of a thermostatic pressure sending valve '28. Chamber 23a is connected through pipe 32 to reservoir 33 and has an escape orifice 280 to permit chamber 28a to slowly vent to atmosphere. Valve 28 has a bimetallic element 281) which is secured to the valve housing and which is adapted to vary the position of a valve member 28d separating chamber 2311 from pipe 32. Bimetallic element 28b is subjected to the temperature of the turbine motive gas at a predetermined point in the turbine, preferably the inlet end thereof. A spring 28 exerts a predetermined biasing force against bimetallic element 28b to maintain valve member 28:! closed until the temperature of the turbine motive gas reached a predetermined value. A needle valve 29 and a volume tank 30 are preferably connected in pipe 2! to delay the transmission of pressure changes from chamber 28a to chamber 3ie.

Input chambers 3H2, 3lc have impressed thereon through a pipe 35 and a pipe 46 input pressures from the output chamber 34a of a governor repeater totalizer 3 similar to totalizer 3!. This input pressure to chamber 3H) is applied directly from pipe 49, while chamber tie is connected to pipe 48 through a needle valve or restricting orifice 35 and a volume tank 31 to delay the transmission of changes in pressure in pipe 58 to chamber 310. Supply port tip is connected to reservoir 33 through a pipe 38 joining pipe 32. Input chambers 34b, 340 of totalizer 34 are connected through a pipe 39 to the output port 41a of an adjustable governor means 4i. Governor 4! comprises a shaft 42 driven by shaft H through gearing 43 at a speed proportional to the speed of turbine 6. A flyball mechanism 44 on shaft 42 controls the movement of a double piston valve having pistons Mb, ilo reciprocable in the governor housing Md. Housing 4 l d is provided with an inlet port Me connected by a pipe 45 to a suitable source 90 of oil under Pressure. Housing did is further provided with an exhaust port 4! connected by a pipe 46 returning oil to source 98. A sleeve valve 4| ghaving control ports 41h, M12 is telescopically'mounted in housing ild and is movable therein. Movement of sleeve valve ily varies the position at which pistons Mb, Me connect outlet port ila to inlet port ile and exhaust port 4! respectively, to vary the speed setting of the governor.

When turbine 6 is running at the desired speed, pistons Mb, file uncover approximately one-half of ports Mh, Mi, respectively, to produce a predetermined output pressure in pipe 39. When turbine 6 is running above the desired speed, flyball mechanism 44 pulls pistons Mb, ilc down to reduce the open area of port Gift and to increase the open area of port ili to thereby reduce the output pressure to pipe 39. When turbine ii is running considerably overspeed, piston lb completely closes port 4m and piston tic completely opens port Eli to reduce the governor output pressure to zero. On underspeed conditions, the pistons i ii), 6 I 0 move upward to thereby increase the output pressure in pipe 39.

Valve My is secured to an arm 41 pivoted at one end thereof on a pivot member 48 and connected at the other end thereof to the movable piston rod 5 la of a speed setting motor 5 I. A piston 5lb connected to rod 5|a is urged upward by a spring 550 and a variable air pressure is admitted to motor 5| above piston 5H2 through an inlet port 5| d to vary the position of arm 41 and sleeve valve Hg in response to variations in the pressure admitted to port 5id. Motor 5| is provided with a projecting stud or stop 5le which limits the upward travel of piston Ho and arm 5m to provide a minimum speed setting for governor iii. Port did is connected through a pipe 52 and a restricting orifice IT to the output chamber 53a of a speed totalizer 53 having input chambers 53b, 53c and a supply port 53p connected to pipe 35 and reservoir 33 through a pipe 54. A spring 5322 is provided between the totalizer housing and diaphragm 53:1 to introduce into the totalizer a predetermined biasing force opposing the input pressures in chambers 53b, 53c.

Input chamber 53b is connected through a pipe 56 to the output chamber 55a of manually operable pneumatic throttle valve means 55 having a supply port 55p connected to reservoir 33 through a pipe 5?. Throttle valve means 55 is similar in operation to totalizers 3!, 3 3, 53, in that the output pressure in chamber 55a is dependent upon the pressures acting against the diaphragms 552', 55 Diaphragms 55i, 557' are urged to the left by a spring 5570 which is compressed a variable amount by a rotatable cam 58 and a follower 55. Diaphragms 552', 55 are secured to a movable member 55m having an exhaust port 551* com-' municating with atmosphere and adapted to be variably opened by stem 551i. Movement of the diaphragms to the left closes exhaust port 557 and. opens supply port 55p to admit air to chamber 55a and pipe 56 until the pressures on diaphragms 551', 557' are balanced, causing the diaphragms to move to the right to close the supply port 5517. Similarly, a decrease in the pressure of spring 55k causes the diaphragms to move to the right to open exhaust port 551 to exhaust pressure in chamber 55a to atmosphere until the pressures on the diaphragms are again balanced.

Cam 58 is rotated by a throttle handle 6! operable by the engineer or operator of the turbine. The lowest fuel position of throttle handle 6| is the idling position, during which spring 55k is compressed a predetermined amount to produce a predetermined minimum output pressure in chamber 55a. The output pressure in chamber. 55a increases from this predetermined minimum value as throttle handle El is moved from the idling position, so that throttle 55 produces in output chamber 55a a control pressure which increases with the extent of movement of throttle handle 6i from the lowest fuel position. Movement of throttle handle GI also actuates a switch 60 having contacts Sea and a segment 6%. Movement of throttle handle 6! causes segment 69b to engagecontacts 60a to connect coil I do of relay I!) to a battery 62.

Input chamber 530 of speed totalizer 53 is connected through a pipe 53 to the output chamber 64a of an ambient thermostatic pressure sending valve 64. Valve 64 has a bimetallic element 642) secured to valve housing 640 and adapted to vary the opening of a valve member 6 d controlling an exhaust port Me in response to variations in the ambient temperature. Chamber E la is connected through a pipe 65 and pipe 5'! to reservoir 33, and variations in the position of valve member 64d vary the area of the escape orifice of atmosphere exhaust port 546 to thereby vary the pressure transmitted to chamber 53c through pipe 63 in response to variations in the ambient temperature.

A fuel guard totalizer 65 having an output chamber 66a, a pair of input chambers 65b, 66c and a supply port 66p is provided to aid in controlling the output of fuel totalizer 3i. Input chamber 561) is connected through a pipe 5? and pipe 35 to the output chamber 34a of governor repeater totalizer 34, and input chamber 560 is connected to pipe 35 and chamber 34a through a pipe 58 having a solenoid valve 89 therein. Valve 69 has an operating coil 653a which, when energized, opens valve 69 to transmit pressure from pipe 35 to chamber 55c. Supply port diip of totalizer 66, instead of being connected to reservoir 33, is connected through a pipe H and pipe 55 to output chamber 55a of throttle valve 55, so that the pressure in output chamber 86a is limited by the output pressure of throttle valve 55. Output chamber 66a is connected through pipes 12, 13 to input chambers 3| (1, Mi, respectively, of fuel totalizer 3!. Branch pipe 14 also connects chamber 65a to opposing input chamber 3ig through a restricting orifice i5 and a volume tank 15. A solenoid bypass valve 49 having an operating coil 49a is connected to pipe 14 to bypass orifice 15 upon energization of coil 49a.

The output pressure from governor repeater totalizer 34 is transmitted through pipes 35 and to fuel totalizer 3i and to the input chambers Mb, 8ic, ld of an excitation totalizer 8|. Pipe 35 is connected directly to input chambers 31?), 8 lo and is connected through a restricting orifice 82 and a volume tank 83 to chamber 8 id. A solenoid bypass valve similar to valve 49 is connected across restricting orifice 82 to bypass this orifice upon energizaticn of coil 50a. Tctalizer 8| has a supply port 8i p connected to reservoir 33 through a pipe 84, and has an output chamber Bic connected through a pipe 85 to the input chamber 851) of a pneumatic positioner 8i). Positioner 85 has a flexible diaphragm 852 connected to an arm 85c forming an adjustable tap on resistor 2|. The movement of diaphragm 860 is controlled by the difference between the input pressure in chamber 36?) and the pressure exerted by a spring 853, so that the resistance of resistor 2! is varied in response to variations in the output pressure of totalizer 81. Arm 866 also carries a bridging member 390. adapted to close contacts 891) of a switch S9 for connecting coils 49a, 50a, 59a to a battery 9| to cause valves 49,

50, 69 to open upon predetermined movement of arm 86c. A similar pneumatic positioner 8'! having a diaphragm 81c and an arm 812 is provided to adjust the resistance of resistor 22. Input chamber 811) is connected through a pipe 88 to pipe H and the output chamber 550. of throttle valve 55.

The turbine is operated in two phases, during the first of which the turbine speed is held constant at a predetermined minimum value and the temperature of the motive gas supplied to the turbine is increased to increase the turbine power. When the motive gas temperature reaches a predetermined maximum value, the turbine enters the second phase of its operation during which the motive gas temperature is maintained constant at the predetermined maximum value and the turbine speed is increased to increase turbine power. The turbine is started from rest by suitable turning gear (not shown) and when the turbine becomes self-sustaining, the turbine may be loaded by movement of throttle handle 6! from the idling position.

In the idling position, cam 58 compresses spring 55%: the predetermined amount to produce the predetermined minimum output pressure in chamber 55a. This output pressure is transmitted through pipe 55 to inputchamber 53b of speed totalizer 53, and chamber 530 receives a control input pressure from ambient thermostatic sender 64. These pressures tend to increase the output pressure in chamber 53a to increase the speed setting of governor 4|, by spring 531; introduces a predetermined biasing force into totalizer 53 opposing the pressures in chambers 53b, 530, so that the output pressure of totalizer 53 does not increase until the sum of the pressures in chambers 53b, 53c exceeds the pressure of spring 5312. Therefore, stop 5Ie maintains governor 41 at its predetermined minimum speed setting.

The governor hydraulic output pressure is transmitted through pipe 39 to chambers 34b, 340 of repeater totalizer 34 Where the hydraulic pressure is converted to a pneumatic output pressure in chamber 3%. The pressure from chamber 34a is transmitted through pipes 35, 61 to input chamber 65b of fuel guard totalizer 56 to control the output pressure in chamber 65a. It will be noted that the output pressure of totalizer 66 is limited by the position of throttle handle 6!, since the output pressure from throttle valve 55 is supplied to supply port 66p. The output pressure from chamber 55a is impressed on input chamber 3Icl of the fuel totalizer 3! to control the output pressure in chamber 3| a. The pressure in chamber 31a is transmitted through pipe 26 to actuator 29, to cause valve 24 to supply to burner 23 the fuel required to maintain the speed of the turbine at the predetermined minimum value set by the governor. In the idling position, contacts 65a of switch 60 are not closed so that armature i311 and field winding 131) are not energized and motor 13 does not rotate.

When throttle handle Si is moved from the idling position to the first traction position, contacts and close to connect armature Ma and field winding |3b to armature l2a, causing rotation of motor i3. This throttle movement also produces an increase in throttle output pressure which supplies a transient excess in fuel signal to chambers 3 Id, 3 I f of fuel totalizer 3i through fuel guard totalizer 66 to aid the turbine in rapidly developing the horsepower required to meet the new load. The effect of this transient 7 fuel increase is gradually canceled by the buildup of pressure in opposing chamber 319 through restricting orifice '15 and volume tank 16. At the same time, pressure from throttle valve 55 is transmitted through pipes H, 88 to chamber 812) of positioner 81 to cause movement of diaphragm 810 for decreasing the amount of resistor 22 connected in series with field winding No. This action increases the voltage of armature 12a to increase the loading of turbine 6. Turbine 6 consequently slows down below the minimum speed setting and governor 4|, sensing an underspeed condition, increases the output pressure in pipe 39. This pressure increase successively increases the output pressures of totalizers 34, 6S, 3!, as described above, to increase the fuel supplied to burner 23 to meet the new power requirements.

The above increase in output pressure from governor repeater totalizer 34 is also impressed directly on chamber 3lb of totalizer 31 where it causes a transient increase in output pressure in pipe 26 and a transient increase in fuel to burner 23 to prevent the turbine speed from falling too far below the set value before the increased pressure from fuel guard totalizer B5 is effective to increase fuel. This transient effect in chamber 3!?) is canceled by the gradual buildup of pressure in opposing chamber sic through needle valve 36 and volume tank 3?.

As the throttle is advanced further to call for more turbine power, positioner arm file moves along resistor 22 to increase turbine loading and power until all of the resistance of resistor 22 is removed from the circuit of field winding il'c. the amount of fuel which fuel guard totalizer 5E and fuel totalizer 3! permit to flow to burner 23 is in suflicient to maintain the turbine speed at the desired value under the increased load, governor AI will sense an underspeed condition and therefore increase the output pressure in pipe 39 and repeater totalizer 34. This increased pressure is transmitted from totalizer 35 through pipe 35 to chambers 85b, 81c, Sid of excitation totalizer 88 where it acts to decrease the pressure in output chamber 81a.

A decrease in the pressure of output chamber Bic permits spring 88] to push diaphragm dlic downward to thereby increase the amount of resistor 2! connected in circuit with field winding l'lc. This action reduces the current in field winding lie to decrease the loading of turbine 6 and thereby permit the turbine to come up to the desired speed. lhe pressure changein pipe 35 is impressed directly on chambers 85b, tic and is impressed on chamber 85d through needle valve 32 and volume tank 83 to produce a transient over-correction of the resistance of resistor 2! to aid in rapidly bringing the'turbine to the desired speed.

When arm 86c moves from its all-resistanceout position shown in the drawing, bridging member 35a closes contacts 8% to connect coils 49a, 58a, 69a to battery s1. This action opens valves 39 and 5G to bypass needle valves it and 82 to thereby eliminate the transient fuel and excitation changes described above. Closure of contacts 3% also causes opening of valve 59 to permit air from pipe 35 to enter input chamber 660. This action doubles the pressure forcing stem Sfin to open supply port 65p so that this port is maintained open to permit air pressure from throttle valve 55 to go directly through pipe H, supply port 56p, output chamber 66a and through pipe 72 to fuel totalizer 3!. This results in transferring fuel control from the governor to the thottle,

although the governor is still operative to control fuel in case of extreme overspeed, as will be described hereinafter. It will be understood from the description thus far that until valve 69 opens, the fuel rate to burner 23 is controlled by the governor rather than by the throttle. This is so because the minimum output pressure from throttle valve 55 is great enough to set a fuel rate in excess of that required to maintain the turbine at the predetermined minimum speed, so that the governor cuts back the fuel rate by permitting only a portion of the throttle valve output pressure to pass through fuel guard totalizer ES to fuel totalizer 3i.

The above described increases in fuel raise the temperature of the motive gases in combustion chamber i and turbine E, and as throttle handle 8! is advanced further, the temperature of the motive gas at the inlet end of the turbine reaches the maximum value to which the turbine may be subjected. The position of throttle handle til at which this maximum inlet temperature is reached varies with the ambient temperature, the maxi mum temperature being reached at a higher throttle position and throttle valve output pressure when the ambient temperature is low than when the ambient temperature is high. Thermostatic sender 64, throttle 55 and speed totalizer 53 are so designed and adjusted that the turbine motive gas is always at the predetermined maximum temperature when the pressures in chambers 53b, 53c exceed the pressure of bias spring 531: by the predetermined amount required to change the governor speed setting from the minimum value. Thus, the turbine transfers from the first phase of operation to the second phase of operation when the motive gas reaches the predetermined maximum value, whichis independent of throttle position.

When the turbine temperature reaches the predetermined maximum value, further movement of throttle handle 6! increases the output pressure of throttle valve 55 to increase the pressure in chamber 531). However, this pressure increase in chamber 53b is not transmitted immediately to motor 5| to increase the setting of governor 4i owing to the delaying effect of orifice H. This increased throttle movement also increases the pressure transmitted through pipe ll to fuel guard totalizer 66 and fuel totalizer 3! to increase the fuel supplied to burner 23. Any increase in fuel to burner 23 will tend to increase the turbine temperature above the maximum value and thermostatic sender 28 therefore tends to increase the pressure in pipe 27 and chamber Elie to decrease the fuel to burner 23. However, restricting orifice 29 and volume tank 33 delay the transmission of this increased pressure so that sender 28 does not immediately act to reduce the fuel. Thus, the increased power made available by the increased temperature is utilized to accelerate the turbine to the increased speed. Restricting orifice ll between totalizer 53 and motor 5| is so adjusted that the governor speed setting is increased simultaneously with the increase in turbine speed occasioned by the increased fuel and temperature, so that the governor output pressure does not change during this fuel and speed increase.

Thus, throttle valve 55 and governor d! act ointly to vary the power delivered by the turbine in response to movement of throttle handle 6!. Although throttle valve 55 is normally operative to control the fuel to burner 2 governor 4! may reduce the burner fuel under certain conditions. If the turbine over-speeds or when throttle handle SI is moved to a decreased speed position, gov- 9 ernor 4| normally increases the excitation of generator l2 to increase the turbine loading to return the speed to the desired value. However, if the governor is unable to return the turbine speed to the desired value, even when all the resistance of resistor 2| is removed from the field circuit, and the turbine continues to overspeed, the output pressure from governor 4| and governor repeater totalizer 35 drops to zero. This action reduces the pressure in input chambers 66b, 660 of the fuel guard totalizer to zero, causing closing of supply port 56p and opening of exhaust port 66 to reduce the pressure in pipe 12 and input chamber 3161 to zero. This in turn reduces the output pressure in chamber 3m to reduce the fuel to burner 23 and thereby return the turbine to the desired speed.

- Thermostatic sender 28 is operative to reduce the burner fuel if the turbine temperature tends to exceed the predetermined maximum value. Needle valve 23 and volume tank 33 delay the transmission of changes in air pressure from sender 28 to chamber 346 so that sender 28 does not operate to limit the opening of fuel valve 24 during transient increases in the temperature of the turbine motive gas above the predetermined maximum value, such as are encountered during acceleration and deceleration of the turbine.

To reverse the locomotive, any suitable known means may be provided to reverse the direction of current flow in field winding IS?) with respect to its direction for forward movement, so that motor armature [3a rotates in the opposite direction. The remainder of the operation of the system for reverse movement of the locomotive is the same as that described above for forward movement.

Although but one embodiment has been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing rrom the spirit of the invention or from the scope of the appended claims. Features disclosed but not claimed herein are claimed in application of Harold E. Reichert, Serial Number 236,544, filed July 13, 1951.

It is claimed and desired to secure by Letters Patent:

1. In a control system for a combustion chamber supplyin motive gas to a gas turbine, the combination of a fuel regulating valve for controlling the flow or fuel to said chamber, an adjustable governor responsive to the speed of said turbine for controlling said fuel valve, a totalizing device for impressing on said governor a variable output signal responsive to a plurality of control signals for controlling the speed setting of said governor, manually operable throttle means for impressing on said totalizing device a first control signal, means responsive to the ambient temperature for impressing on said totalizing device a second control signal cumulative with respect to said first control signal, biasin means connected to said totalizing device for impressing on said device a substantially constant third control signal opposing said first and said second signals, and limiting means on said governor for producing a minimum speed setting of said governor, the output signal from said totalizing device required to change the governor speed setting from said minimum setting having a predetermined value, whereby said throttle is inoperative to change said governor speed settin until the sum of said first and said second signals exceeds said third signal by said predetermined value, said second control signal varying with the 10 ambient temperature so that the temperature of said motive gas is always at a predetermined maximum value when said governor speed setting changes from said minimum setting to a higher setting.

2. In a control system for a combustion chamber supplying motive gas to a gas turbine, the combination of a fuel regulating valve for controlling the flow of fuel to said chamber, a source of air under pressure, an adjustable governor responsive to the speed of said turbine for controlling said fuel valve, a pneumatic totalizing device connected to said source for impressing on said governor a variable output pressure responsive to three setting of said governor, manually operable throttle means connected to said source for impressing on said totalizing device a first control pressure, pneumatic means responsive to the ambient temperature connected to said source for impressing on said totalizing device a second control pressure cumulative with respect to said first control pres-- sure, biasing means connected to said totalizing device for impressing on said device a substantially constant third control pressure opposing said first and said second pressures, and limiting means on said governor for producing a minimum speed setting of said governor, the output pressure from said totalizing device required to change the governor speed setting from said minimum setting having a predetermined value, whereby said throttle is inoperative to change said governor speed setting until the sum of said first and said second pressures exceeds said third pressure by said predetermined value, said second control pressure varying with the ambient temperature so that the temperature of said motive gas is always at a predetermined maximum value when said governor speed setting changes from said minimum setting to a higher setting.

3. In a control system for a combustion chamber supplying motive gas to a gas turbine driving an electric generator, the combination of a fuel regulating valve for controllin the flow of fuel to said chamber, a source of air under pressure, adjustable resistance means for varying the excitation of said generator, first pneumatic means for controlling the resistance of said resistance means, an adjustable governor responsive to the speed of said turbine for controlling said fuel valve, a pneumatic totalizing device connected to said source for impressing on said governor a variable output pressure responsive to three control pressures for controlling the speed setting of said governor, manually operable throttle means connected to said source for producing a first control pressure dependent upon the position of said throttle means, means connecting said throttle means to said pneumatic totalizing device and to said first pneumatic means to impress said first control pressure thereon, second pneumatic means responsive to the ambient temperature connected to said source for impressing on said totalizing device a second control pressure cumulative with respect to said first control pressure, biasing means connected to said totalizing device for impressing on said device a substantially constant third control pressure opposing said fi st and said second control pressures, and limiting means on said governor for producing a minimum speed setting of said governor, the output pressure from said totalizing device required to change the governor speed setting from said minimum setting having a predetermined value, whereby said throttle means controls said first control pressures for controlling the speed pneumatic means to control the loadingof said speed setting.

4. In a control system for a combustion chamber supply motive gas to a gas turbine driving an electric generator, the combination of a fuel regulating valve for controlling the flow of fuel to said chamber, adjustable resistance means for varying the excitation of said generator, first control means for controlling the resistance of said resistance means, an adjustable governor responsive to the speed of said turbine for controlling said fuel valve, a totalizing device for impressing on said governor a variable output signal responsive to three control signals for controlling the speed setting of said governor, manually operable throttle means for producing a first control signal dependent upon the position of said throttle means, means connecting said throttle means tc said totalizing device and to said first control means to impress said first control signal thereon, second control means responsive to the ambient temperature for impressing on said totalizing device a second control signal cumulative with respect to said first control signal, bias ng means connected to said totalizing device for impressing on said totalizing device a substantially constant third control signal opposing said first and said second control signals, and limiting means on said governor for producing a minimum speed setting of said governor, the output signal from said totalizing device required to change the governor speed setting from said minimum setting having a predetermined value, whereby said throttle means controls said first control means to control the loading of said turbine and said throttle means is inoperative to change said governor speed setting until the sum of said first and said second control signal exceeds said third signal by said predetermined value, said second control signal varying with ambient temperature so that the temperature of said motive gas is always at a predetermined maximum value when said governor speed setting changes from said minimum speed setting to a higher speed setting.

5. In a control system for a combustion chamber supplying motive gas to a gas turbine driving an electric generator, the combination of a fuel regulating valve for controlling the flow of fuel to said chamber, a source of air under pressure, first adjustable resistance means and second adjustable resistance means for varying the excitation of said generator, first pneumatic means and second pneumatic means for controlling the resistance of said first and said second resistance means, means including an adjustable governor for producing a first control pressure dependent upon the speed of said turbine, a pneumatic totalizing device connected to said source for impressing on said governor a variable output pressure responsive to three control pressures for controlling the speed setting of said governor, means connecting said governor to said second pneumatic means and to said fuel. valve to vary the resistance of said second resistance means and to vary the fuel admitted to said chamber in response to variations in said first control pressure,

manually operable throttle means connected to said source for producing a second control pressure dependent upon the position of said throttle means, means connecting said throttle means to said pneumatic totalizing device and to said first pneumatic means to impress said second control pressure thereon, third pneumatic means responsive to the ambient temperature connected to said source for impressing on said totalizing device a third control pressure cumulative with respect to said second control pressure, biasing means connected to said totalizing device for impressing on said totalizing device a substantially constant fourth control pressure opposing said second and said third control pressures, and limiting means on said governor for producing a minimum speed setting of said governor, the output pressure from said totalizing device required to change the governor speed setting from said minimum setting having a predetermined value, whereby said throttle means and said governor control said first and said second pneumatic means to control the loading of said turbine and said throttle means is inoperative to change said governor speed setting until the sum of said second and said third control pressures exceeds said fourth pressure by said predetermined value,'and said third control pressure varying with ambient temperature of said motive gas is always at a predetermined maximum value when said governor speed setting changes from said minimum speed setting to a higher speed setting.

6. In a control system for a combustion chamber supplying motive gas to a gas turbine driving an electric generator, the combination of a fuel regulating valve for controlling the flow of fuel to said chamber, a source of air under pressure, first adjustable resistance means and second adjustable resistance means for varying the excitation of said generator, first pneumatic means and second pneumatic means for controlling the resistance of said first and said second resistance means, means including an adjustable governor for producing a first control pressure dependent upon the speed of said turbine, a pneumatic totalizing device connected to said source for impressing on said governor a variable output pressure responsive to three control pressures for controlling the speed setting of said governor, means connecting said governor means to said second pneumatic means and to said fuel valve to vary the resistance of said second resistance means and to vary the fuel admitted to said chamber in response to variations in said first control pressure, manually operable throttle means connected to said source for producing a second control pressure dependent upon the position of said throttle means, means connecting said throttle means to said pneumatic totalizing device and to said first pneumatic means to impress said second control pressure thereon, third pneumatic means responsive to the ambient temperature connected to said source for impressing on said totalizing device a third control pressure cumulative with respect to said second control pressure, spring means connected to said totalizing device for impressing on said device a substantially constant fourth control pressure opposing aid second and said third control pressures, and limiting means on said governor for producing a minimum speed setting of said governor, the output pressure from said totalizing device required to change the governor speed setting from said minimum setting having a predetermined value, whereby said throttle means and said governor control said first and said second pneumatic mean to control the loading of said turbine and said throttle means is inoperative to chan e said governor speed setting until the sum of said second and said third control pressures exceeds said fourth pressure by said predetermined value, said third control pressure varying with ambient temperature so that the temperature of said motive gas is always at a predetermined maximum value when said governor speed setting changes from said minimum speed setting to a higher speed setting.

In a control system for a combustion chamber supplying motive gas to a ga turbine, the combination of a source of air under pressure, a fuel regulating valve adapted to be opened by air from said source for controlling the how of fuel to said chamber, a first pneumatic totalizing device connected to said source for impressing on said fuel valve a variable output pressure responsive to two control pressure for controlling the opening of said valve, an adjustable governor for impressing on said first totalizing device a first control pressure dependent upon the speed of said turbine, first pneumatic means connected to said source for impressing on said first total?- ing device a second control pressure dependent upon the temperature of said motive gas at a, predetermined point of said turbine, said second control pressure limiting the opening of said valve as the temperature of said motive gas increases to prevent said temperature from substantially exceeding a predetermined maximum value, a second pneumatic totalizing device connected to said source for impressing on said governor a variable output pressure responsive to three control pressures for controlling the speed setting of said governor, manually operable throttle means connected to said source for impressing on said second totalizing device a third control pressure, second pneumatic means responsive to the ambient temperature connected to said source for impressing on said second totalizing device a fourth control pressure cumulative with respect to said third control pressure, biasing means connected to said second totalizing device for impressing on said second totalizing device a substantially constant fifth control pressure opposing said third and said fourth pressures, and limiting means on said governor for producing a minimum speed setting of said governor, the output pressure from said second totalizing device required to change the governor speed setting from said minimum setting having a predetermined value, whereby said throttle means is inoperative to change said governor setting until the sum of said third and said fourth pressures exceeds said fifth pressure by said predetermined value, said fourth control pressure varying with the ambient temperature so that the temperature of said motive gas is always at said predetermined maximum value when said governor speed setting changes from said minimum speed setting to a higher speed setting.

8. In a control system for a combustion chamber supplying motive gas to a gas turbine, the combination of a source of air under pressure, a fuel regulating valve adapted to be opened by air from said source for controlling the flow of fuel to said chamber, a first pneumatic totalizing device connected to said source for impressing on said fuel valve a variable output pressure responsive to two control pressures for controlling the opening of said valve, an adjustable governor for impressing on said first totalizin device a first control pressure dependent upon the speed of said turbine, first pneumatic means connected to said source for producing a second control pressure dependent upon the temperature of said motive gas at a predetermined point in said turbine, a volume tank, a needle valve, means connecting said first pneumatic means to first totalizing device through said volume tank and said needle valve to impress said second control pressure on said device, said second pressure limiting the opening of said valve as the temperature of said motive gas increases to prevent said temperature from substantially exceeding a predetermined maximum value, said volume tank and said needle valve delaying the transmission of changes in said second control pressure from said first pneumatic means to said totalizing device to prevent limiting of the opening of said fuel valve in response to transient variations in the temperature of said motive gas above said predetermined maximum value, a second pneumatic totalizing device connected to said source for impressing on said governor a variable output pressure responsive to three control pressures for controlling the speed setting of said governor, manually operable throttle means connected to said source for impressing on said second totalizing device a third control pressure, second pneumatic means responsive to the ambient temperature connected to said source for impressing on said second totalizing device a fourth control pressure cumulative with respect to said third control pressure, biasing means connected to said second totalizing device for impressing on said second device a substantially constant fifth control pressure opposing said third and said fourth pressures, and limiting means on said governor for producing a minimum speed setting of said governor, the output pressure from said second totalizing device required to change the governor speed setting from said minimum setting having a predetermined value, whereby said throttle means is inoperative to change said governor setting until the sum of said third and said fourth pressures exceeds said fifth pressure by said predetermined value, said fourth control pressure varying with the ambient temperature so that the temperature of said motive gas is always at said predetermined maximum value when said governor speed setting changes from said minimum speed setting to a higher speed setting.

9. In a control system for a. combustion chamber supplying motive gas to a gas turbine, the combination of a source of air under pressure, a fuel regulating valve adapted to be opened by air from said source for controlling the fiow of fuel to said chamber, a first pneumatic totalizing device connected to said source for impressing on said fuel valve a variable output pressure responsive to two control pressures for controlling the opening of said valve, an adjustable governor for producing a hydraulic pressure dependent upon the speed of said turbine, a second fluid pressure totalizing device connected to said source and having an output chamber and a pair of input chambers, means for impressing said hydraulic pressure upon said input chambers to produce in said output chamber a first control pressure proportional to said hydraulic pressure, means for impressing said first control pressure upon said first totalizin device, first pneumatic means connected to said source for impressing on said first totalizing device a second control pressure dependent upon the temperature of said motive gas at a predetermined point of said turbinesaid second control pressure limiting the opening of said valve as the temperature of said motive gas increases to prevent said temperature from substantially exceeding a predetermined maximum value, a second pneumatic totalizing device connected to said source for impressing on said governor a variable output pressure responsive to three control pressures for controllin the speed setting of said governor, manually operable throttle means connected to said source for impressing on said second totalizing device a third control pressure, second pneumatic means responsive to the ambient temperature connected to said source for impressing on said second totalizing device a fourth control pressure cumulative with respect to said third control pressure, biasing means connected to said second totalizing device for impressing on said second totalizing devic a substantially constant fifth control pressure opposing said third and said fourth pressures, and limiting means on said governor for producing a minimum speed setting of said governor, the output pressure from said second totalizing device required to change the governor speed setting from said minimum setting having a predetermined value, whereby said throttle means is inoperative to change said governor setting until the sum of said third and said fourth pressure exceeds said fifth pressure by said predetermined value, said fourth control pressure varying with the ambient temperature so that the temperature of said motive gas is always at said predetermined maximum value when said governor speed setting changes from said minimum speed setting to a higher speed setting.

10. In a control system for a combustion chamber supplying motive gas to a gas turbine, the combination of a source of air under pressure, a fuel regulating valve adapted to be opened by air from said source for controlling the flow of fuel to said chamber, a first fluid pressure totalizing device connected to said source for impressing on said fuel valve a variable output pressure responsive to a plurality of control pressures for controlling the opening of said valve, said device having a plurality of input chambers, an adjustable governor for producing a hydraulic pressure dependent upon the speed of said turbine, a second fluid pressure totalizing device connected to said source and having an output chamber and a pair of input chambers, means for impressing said hydraulic pressure upon said pair of input chambers to pro-' duce in said output chamber a first control pressure proportional to said hydraulic pressure, means connecting said output chamber to two of said input chambers of said first totalizing device, a volume tank, a needle valve connected with said volume tank between said output chamber and one of said two input chambers, whereby sudden variations in the speed of said turbine produce a, transient operation of said fuel valve to correct said variations, a third totalizing device connecting said output chamber to a third said input chamber of said first totalizing device, first pneumatic means connected to said source for impressing on said first totalizing device a second control pressure dependent upon the temperature of said motive gas at a predetermined point of said turbine, said second control pressure limiting the opening of said valve as the temperature of said motive gas increases to prevent said temperature from substantially exceeding a predetermined maximum value, a fourth pneumatic totalizing device connected to said source for impressing on said governor a variable output pressure responsive to three control pressures for controlling the speed setting of said governor, manually operable throttle means connected to said source for impressing on said fourth totalizing device a third control pressure, second pneumatic means responsive to the ambient temperature connected to said source for impressing on said fourth totalizing device a fourth control pressure cumulative with respect to said third control pressure, biasing means connected to said fourth totalizing device for impressing on said fourth totalizing device a substantially constant fifth control pressure opposing said third and said fourth pressures, and limiting means on said governor for producing a minimum speed setting of said governor, the output pressure from said fourth totalizing device required to change the governor speed setting from said minimum setting having a predetermined value, whereby said throttle means is inoperative to change said governor setting until the sum of said third and said fourth pressures exceeds said fifth pressure by said predetermined value, said fourth control pressure varying With the ambient temperature so that the temperature of said motive gas is always at said predetermined maximum value when said governor speed setting changes from said minimum speed setting to a higher speed setting.

11. In a control system for a combustion chamber supplying motive gas to a, gas turbine driving an electric generator, the combination of a source of air under pressure, a fuel regulating valve adapted to be opened by air from said source for controlling the flow of fuel to said chamber, means including an adjustable governor for producing a first control pressure dependent upon the speed of said turbine, adjustable resistance means for varying the excitation of said generator to vary the loading of said turbine, first pneumatic means for controlling the resistance of said resistance means, a volume tank, a needle valve connected with said volume tank between said governor and said first pneumatic means, whereby variations in said first control pressure produce transient variations in the adjustment of said resistance means, a first pneumatic totalizing device connected to said source for impressing on said fuel valve a variable output pressure responsive to two control pressures for controlling the opening of said valve, means for impressing said first control pressure on said first totalizing device, second pneumatic means connected to said source for impressing on said first totalizing device a second control pressure dependent upon the temperature of said motive gas at a predetermined point of said turbine, said second control pressure limiting the opening of said valve as the temperature of said motive gas increases to prevent said temperature from substantially exceeding a predetermined maximum value, a second pneumatic totalizing device connected to said source for impressing on said governor a variable output pressure responsive to three control pressures for controlling the speed setting of said governor, manually operable throttle means connected to said source for impressing on said second totalizing device a third control pressure, third pneumatic means responsive to the ambient temperature connected to said source for impressing on said second totalizing device a fourth control pressure cumulative with respect to said third control pressure, biasing 17 means connected to said second totalizing device for impressing on said second totalizing device a substantially constant fifth control pressure opposing said third and said fourth pressures, and limiting means on said governor for producing a minimum speed setting of said governor, the output pressure from said second totalizing device required to change the governor speed setting from said minimum setting having a predetermined value, whereby said throttle means is inoperative to change said governor speed setting until the sum of said third and said fourth pressures exceeds said fifth pressure by said predetermined value, said fourth control pressure varying with the ambient temperature so that the temperature of said motive gas is always at said predetermined maximum value when said governor speed setting changes from said minimum speed setting to a higher speed setting.

STANLEY W. JAMES.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date Seippel Mar. 12, 1940 Seippel Nov. 25, 1941 Doran Dec. 7, 1943 Sedille Dec. 9, 1947 Greenland Mar. 20, 1948 Atkinson May 25, 1948 Chamberlin Aug. 23, 1949 Multhaup June 6, 1950 Schorn July 11, 1950 Klinge Mar. 20, 1951 Starkey et al June 26, 1951 May et a1 July 3, 1951 

